Problem installing ram on laptop

Well I got this P30-JC1 Toshiba laptop brand new. It comes with 512megs of ddr1 333mhz 2700 ram. So i was thinking i would take out a 512 mb stick from a Compaq laptop and add it to the Toshiba.

The ram is exactly the same as the the Toshiba one but when i install the ram it still only detects 512mb.

Both sticks by themselves work. I have tried both slots alone and both slots work. I even took out the two 512 mb stick from Compaq laptop and put those in the Toshiba, STILL only detects 512. This laptop supports 1.5gigs of ram so what is going on? Let me mention once more that there is nothing wrong with the ram since I have tried each alone.

The only thing i can think of is that the P30 Toshiba doesnt read two 512's as 1gb and that i need an actual 1gb stick of ddr1....

Thanks for the help